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  <div id="layout-content"><div id="function.dechex" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">dechex</h1>
   <p class="verinfo">(PHP 4, PHP 5, PHP 7, PHP 8)</p><p class="refpurpose"><span class="refname">dechex</span> &mdash; <span class="dc-title">十进制转换为十六进制</span></p>

 </div>
 <div class="refsect1 description" id="refsect1-function.dechex-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>dechex</strong></span>(<span class="methodparam"><span class="type">int</span> <code class="parameter">$num</code></span>): <span class="type">string</span></div>

  <p class="para rdfs-comment">
   返回一字符串，包含有给定
   <code class="parameter">num</code>
   参数的十六进制表示。
  </p>
  <p class="para">
   所能转换的最大数值为十进制的
   <strong><code>PHP_INT_MAX</code></strong><code class="literal"> * 2 + 1</code> (或
   <code class="literal">-1</code>)：在 32 位平台上是十进制的 <code class="literal">4294967295</code>，其 <span class="function"><strong>dechex()</strong></span> 的结果为 <code class="literal">ffffffff</code>。
  </p>
 </div>

 <div class="refsect1 parameters" id="refsect1-function.dechex-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>
    
     <dt>
<code class="parameter">num</code></dt>

     <dd>

      <p class="para">
       要转换的十进制值
      </p>
      <p class="para">
       PHP 的 <span class="type">int</span> 类型是有符号的，但 <span class="function"><strong>dechex()</strong></span> 处理无符号整数，负正数会以无符号处理。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.dechex-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   <code class="parameter">num</code> 的16进制表示
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-function.dechex-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-3088">
    <p><strong>示例 #1 <span class="function"><strong>dechex()</strong></span> 例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">dechex</span><span style="color: #007700">(</span><span style="color: #0000BB">10</span><span style="color: #007700">)&nbsp;.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">dechex</span><span style="color: #007700">(</span><span style="color: #0000BB">47</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
a
2f
</pre></div>
    </div>
   </div>
  </p>
   <p class="para">
   <div class="example" id="example-3089">
    <p><strong>示例 #2 大整数的 <span class="function"><strong>dechex()</strong></span> 例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">//&nbsp;下面的输出假设是&nbsp;32&nbsp;位平台。<br />//&nbsp;注意输出的所有值一样。<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">dechex</span><span style="color: #007700">(-</span><span style="color: #0000BB">1</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">dechex</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_INT_MAX&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">2&nbsp;</span><span style="color: #007700">+&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">dechex</span><span style="color: #007700">(</span><span style="color: #0000BB">pow</span><span style="color: #007700">(</span><span style="color: #0000BB">2</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">32</span><span style="color: #007700">)&nbsp;-&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
ffffffff
ffffffff
ffffffff
</pre></div>
    </div>
   </div>
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.dechex-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.hexdec.html" class="function" rel="rdfs-seeAlso">hexdec()</a> - 十六进制转换为十进制</span></li>
    <li class="member"><span class="function"><a href="function.decbin.html" class="function" rel="rdfs-seeAlso">decbin()</a> - 十进制转换为二进制</span></li>
    <li class="member"><span class="function"><a href="function.decoct.html" class="function" rel="rdfs-seeAlso">decoct()</a> - 十进制转换为八进制</span></li>
    <li class="member"><span class="function"><a href="function.base-convert.html" class="function" rel="rdfs-seeAlso">base_convert()</a> - 在任意进制之间转换数字</span></li>
   </ul>
  </p>
 </div>

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